Personally, I found the 5005 behaviour easier to program with than the new one, but that's possibly just me..

Nope, not just you. The 5005 way was, more or less, following the standard model of sharing found elsewhere. If I had to describe the new thread model (and I've had to on a few occassions) it is as if it were a slow, bloated fork emulation but with convenience functions for synchronizing access to shared data.